The conventional Venetian blind is composed of a plurality of slats which can be operated by a lifting mechanism to ascend or descend. The lifting mechanism has an outer pull cord which is disposed outside the slats, a slat set pull cord, and a ratchet wheel retaining member. The outer pull cord is exposed to facilitate the pulling of the pull cord by hand. The slat set pull cord is connected with the slat set such that the slat set pull cord is actuated to control the ascending and the descending of the slat set. In the meantime, the slat set in motion is located at a desired level by the ratchet wheel retaining member.
Such a conventional Venetian blind as described above is defective in design in that the exposed pull cord is a potential safety hazard to a playful child who may be strangled accidentally by the pull cord, and that the exposed pull cord is prone to become entangled with a foreign object, and further that the exposed pull cord is vulnerable to becoming intertwined with the slat set.